You can order different layouts on the hardware - though we have no idea how much that may delay an order. But the customization we talk about is the characters you program onto each layer.
For an extreme example, I use Dvorak. Well, that is one of the many standard layouts they offer so no problem. But as I used the TB, I also used the "hot corners" setting. This puts, on a Mac, Command on the left corner of the space bar and Alt on the right. This is in addition to the normal chord approaches for those keys.
Well, I found I was pretty much never using alt - and if I really needed it, I could always use the chords. I decided I wanted another layer mostly to do some things one handed. I had been using the function layer (holding a 2-key chord and whatever other key you programmed) for this. But for one hand, you were pretty much limited to the right hand. That gave limited options since two of those keys were the chord for functions!
So I switched to the emoji layout even though I rarely use emoji. This layout changes the Alt halt corner to be the emoji layer. Now I could reach any key on the right while holding that hot corner (some easier than others, of course). But the emoji keyboard comes only as qwerty. So I had to customize that qwerty layout to be Dvorak. So a LOT of changes. But at least it could be done. I wouldn't be surprised if later we got versions for Dvorak as part of the standard set.
Like I said, that's an extreme case. For most people, you'll make smaller adjustments to fit your situation. Some examples, using qwerty references:
A number of testers, especially in the beginning, had trouble when wanting "p", but hitting delete. So some opted to remove delete from the main layer and just use the green layer for that. Likewise some folks had trouble with hitting Enter instead of the apostrophe. In many places, this would send a message you were typing before you were done.
I tried some of these changes, but just didn't like them. Others do. I found just changing some boundaries worked best for me.
Almost all keys are customizable. I think, on most layers, you can't change Shift, for example. And you can't program the hot corners beyond what they allow (you either have Command and Alt or Command an emoji), but I think they plan on opening that up.
This has been a process. Originally there were more places, at least on some layers, that we couldn't change. Almost no limits now.
Jumps are easy. You have 6 and you get them by hitting two adjacent keycaps across the top. So, QW, WE, ER on the left and similar on the right - there are only 6 possible combinations since the keys you use must be on different keycaps. You can't do RT because they are on the same keycap. I try to set mine up in a pattern I can remember. For example, going from 1 to 6, it might be iPhone, iPad mini, iPad Pro, iMac, MacBook, Bluetooth dongle.
Other chords are to get Command, Alt, Contrl - duplicated on both hands in mirror fashion. And chords for the number pad, locking edit mode, accessing macros and the function layers. Can seem confusing, but you start out with just the most common stuff and gradually add more to your repertoire.
There are no buttons on the space blade. It senses if you are hitting the right or left corner or someplace in between.
Have you looked at the videos at WayTools.com? It shows the first one when you go to the site (have to activate it though), but there are a whole bunch more at the bottom of the screen and it scrolls over for even more. And if you click on some items at the top of the page, there are even more!
No remapping of chords, though you can do something similar. Suppose you want Command-A, but you don't want to use the command chord or hot corner. Well, a key isn't limited to programming just characters. You can include modifiers. Take the Home key on the layout. I could program that to be Command-A. Heck, I could program it to be command/alt/option/shift-A if I wanted! I do some of this on the emoji layer. Right now WT includes a command to copy the screen or a window to the clipboard, but not to the desktop. But I want it on the desktop. There is a key combination (I forget what it is now) which I entered into my customized setup to cover that.
Hangie created some kind of system for his keyboard so he could set it up like a TextBlade before he got into Treg so you might ask him about doing that. Don't know if it works on latest OS.